基于扰动状态概念的煤蠕变本构模型

Constitutive model of coal based on disturbed state concept theory

针对煤矿井下条带法开采留设的煤柱在覆岩压力作用下随着时间推移易发生蠕变现象,考虑到传统蠕变模型难以描述煤体蠕变各个阶段的损伤特性,基于扰动状态概念的理论,选用Kelvin模型描述材料的相对完整状态,将Burgers模型中的黏壶元件用非线性黏壶元件代替描述材料的完全调整状态,引入Weibull分布函数,选取以时间为自变量的扰动因子函数,建立了以扰动因子为权函数的煤体蠕变全过程的本构模型.同时,利用煤样室内蠕变试验数据对基于扰动状态概念下煤体的蠕变模型参数进行了辨识,验证了该模型的合理性,且相对于传统模型有较好的协调性,能够更有效地描述煤体的初始、稳定和加速蠕变阶段的蠕变规律.

Under the action of overburden pressure,the coal pillars retained by strip mining underground are prone to creep over time,showing obvious viscoelastic-plastic characteristics and causing different degrees of damage.Based on the disturbance state concept theory and the deformation characteristics of coal in creep process,Kelvin model is used to describe the relative integrity of materials,and the clay pot in Burgers model is replaced by a non-linear clay pot to describe the fully adjusted state of the material.By introducing Weibull distribution function,the perturbation factor function with time as the independent variable is selected and the constitutive model of the whole creep process of coal is established with perturbation factor as weight function.The parameters of the creep model of coal based on the disturbance state concept are identified by the indoor creep test data,which verifies the rationality of the model.Compared with the traditional model,this model has better compatibility and can well describe the initial,stable and accelerated creep stages of coal.